[tex]E_{(x)}=(\frac{2x-8}{x^2-5x-3x+15}-\frac{1}{x-3})\cdot(x-5)(x+5)=\\
(\frac{2x-8}{x(x-5)-3(x-5)}-\frac{1}{x-3})\cdot (x-5)(x+5)=\\
(\frac{2x-8}{(x-5)(x-3)}-\frac{1}{x-3})\cdot (x-5)(x+5)=\\
\frac{2x-8-x+5}{x-3}\cdot (x+5)=\\
\frac{x-3}{x-3}\cdot(x+5)=x+5
[/tex]
